2D Tolerance Search and N-Dimension Uniform Grid

[matthew-mccall]

This pull request introduces significant generalization and refactoring of the point localization and search infrastructure, preparing the codebase for both 2D and 3D mesh support. The changes include replacing hardcoded 2D structures with dimension-agnostic templates, introducing new search classes and functors for 3D, and improving the robustness and clarity of the point search logic.

Generalization and Refactoring for Dimension-Agnostic Support:

• Introduced template functions and classes such as simplex_bbox, within_bbox, bbox_verts_within_simplex, and simplex_intersects_bbox to generalize bounding box and intersection logic for arbitrary dimensions, replacing 2D-specific implementations. [1] [2] [3] [4]
• Added GridTriIntersectionFunctor3D and corresponding construct_intersection_map_3d to support 3D mesh intersection, alongside renaming and refactoring the 2D functor and intersection map construction for clarity.

Search Infrastructure Modernization:

• Refactored GridPointSearch to GridPointSearch2D and replaced std::optional with std::unique_ptr for the search_ member in OmegaHField, making the design ready for alternative search strategies and consistent with modern C++ practices. [1] [2] [3]

Point Search Logic and API Improvements:

• Enhanced the point search operator to robustly distinguish between vertex, edge, and face hits, using a new tolerance structure (PointSearchTolerances) and improving the logic for nearest element detection and classification. [1] [2] [3]
• Updated result structures and usages to reflect the new naming and dimensionality (e.g., element_id instead of tri_id, GridPointSearch2D::Result), and improved error checking and reporting. [1] [2] [3]

These changes collectively make the codebase more extensible, robust, and ready for future 3D mesh support.

[jacobmerson]

/runtests

[Copilot]

Pull Request Overview

This PR refactors the point search functionality to support both 2D and 3D meshes by introducing a templated base class hierarchy. The main changes include:

• Introduces a PointLocalizationSearch base class templated on dimension
• Renames GridPointSearch to GridPointSearch2D and adds GridPointSearch3D implementation
• Updates the 2D point search algorithm to check for vertices and edges before faces
• Adds tolerance-based matching for vertices and edges
• Removes the UniformGrid default template parameter in favor of explicit specialization

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/pcms/uniform_grid.h	Removes default template parameter and adds explicit 2D/3D type aliases
src/pcms/point_search.h	Introduces base class hierarchy and separate 2D/3D implementations
src/pcms/point_search.cpp	Implements 3D point search and refactors 2D algorithm with tolerance-based matching
test/test_point_search.cpp	Updates tests to use new class names and test new behavior
src/pcms/interpolator/adj_search.hpp	Updates references from GridPointSearch to GridPointSearch2D
src/pcms/adapter/omega_h/omega_h_field.h	Changes from std::optional to std::unique_ptr for polymorphic storage

Comments suppressed due to low confidence (1)

src/pcms/point_search.cpp:656

• In the 3D constructor GridPointSearch3D, querying Omega_h::FACE to Omega_h::EDGE and Omega_h::FACE to Omega_h::VERT adjacencies is incorrect. For 3D tetrahedral meshes, the top-level elements are Omega_h::REGION (tetrahedra), not Omega_h::FACE. These should be mesh.ask_down(Omega_h::REGION, Omega_h::EDGE) and mesh.ask_down(Omega_h::REGION, Omega_h::VERT).

  tris2edges_adj_ = mesh.ask_down(Omega_h::FACE, Omega_h::EDGE);
  tris2verts_adj_ = mesh.ask_down(Omega_h::FACE, Omega_h::VERT);

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[jacobmerson]

@matthew-mccall I started reviewing this, but I realized it's on my fork. Can you close this pull request and re-open it on SCOREC/pcms.

Thanks!